1. Field Of The Invention
The present invention relates to medical ventilator devices for providing breathing assistance for patients, and more particularly, to a ventilator circuit formed by a tube and manifold assembly providing connections between a medical ventilator and the patient.
2. Description Of The Prior Art
Medical ventilator devices are well known in the art and are commonly used with patients whose breathing is sufficiently impaired that mechanical assistance is needed. The most commonly used medical ventilators are of a positive pressure type wherein a mechanical lung cyclically forces air through an inhalation tube.
Following each inhalation, the pressure of the air in the patient's lungs, combined with the elastic recoil properties of the chest wall and lungs, create a pressure gradient which passively causes exhalation through an exhalation tube. The inhalation and exhalation tubes together with other pathways for air traveling to and from the patient form the ventilator circuit.
To accomplish the inhalation and exhalation, a closed, or gas-tight, system of circuit tubing is required. In addition to the inhalation and exhalation tubes, a patient breathing tube must be sealingly connected to the patient's mouth or trachea. This patient breathing tube is then sealingly connected to the inhalation and exhalation tubes which are in turn sealingly connected to the medical ventilator machine. The mechanical lung of the medical ventilator is controlled by a master control device.
To properly control the inhalation and exhalation phases, the master control device utilizes an exhalation valve disposed on the exhalation tube for allowing pressure to be contained during an inhalation phase. The exhalation valve opens during the exhalation phase. The control of this valve by the medical ventilator is accomplished by a pneumatic signal which is conveyed from the ventilator master control device to the exhalation valve by means of an exhalation valve drive tube.
The pressure within the tubing system is monitored by means of a patient air pressure tube which is connected from a position adjacent the patient breathing tube to a pressure sensor on the medical ventilator for communicating this pressure level to the machine. Based on this pressure signal, the medical ventilator can acutate an emergency signal if patient pressure is lost or reduced below a predetermined or set level.
Many medical ventilator machines also incorporate a nebulizer device for introducing regulated amounts of medicine into the air being delivered to the patient through the inhalation tube. The nebulizer is disposed on the inhalation tube pathway and is controlled pneumatically by the master control device. A pneumatic signal controlling the nebulizer and regulating the flow of medication enhanced air is conveyed from the ventilator master control device to the nebulizer by means of a nebulizer drive or control tube connected therebetween.
Medical ventilator machines may also incorporate a means for warming and humidifying the air delivered to the patient. As air flows through the circuit tubing, the warm, moist air condenses in the tubing, and bacteria can grow in this warm and moist environment. If the bacteria is communicated to the patient, an infection can result, and therefore it is necessary to replace or change out the tubing frequently. The changed-out tubing can be sterilized or discarded.
The disconnection, replacement and reconnection of all of the tubing in the ventilator circuit can be dangerous for the patient because many mechanically ventilated patients are dependent on the ventilator for each and every breath they take. Any significant interruption in the breathing cycle can prove harmful to them. This is of extreme importance for critically ill patients who may have no respiratory function other than that provided by the medical ventilator.
As described above, as many as five different tubes or hoses must be replaced in the process of changing out the ventilator circuit tubing. These tubes include the inhalation tube, the exhalation tube, the exhalation valve drive tube, the patient air pressure tube and the nebulizer drive tube. Since each of these tubes has two ends, it will be seen that as many as ten different connections and disconnections can be required for a complete change-out procedure. Making this many connections and disconnections can prove dangerous to the patient as already mentioned. In addition, accidental disconnection can also prove to be dangerous.
The medical ventilator tube and manifold assembly of the present invention solves these problems by providing a ventilator circuit which is more easily connected and disconnected while still insuring secure attachment at all connection sites. Further, the present invention provides a much less time-consuming method of changing out ventilation circuit tubing and is thus safer for the patient.